Serbia's new president, Aleksandar Vucic, has been formally inaugurated in a ceremony attended by many foreign leaders and dignitaries -- and amid protests against what his critics describe as his increasingly tight grip on power in the Balkan country.

The 46-year-old Vucic was sworn in on May 31, succeeding Tomislav Nikolic, at a ceremony in parliament that was marred by protests in Belgrade supported by the majority of opposition parties and leaders.

The more colorful formal ceremony on June 23 at Belgrade’s Palace of Serbia, the seat of government of the former Federal Republic of Yugoslavia, was attended by some 5,000 guests -- including high-level envoys from the United States and Russia, and leaders from across the Balkans.

Once an ultranationalist who served as information minister in the administration of strongman Slobodan Milosevic, Vucic has solidified his grip on power by reinventing himself as a reformer committed to Serbia's drive toward European Union membership.

Vucic's first-round presidential election victory on April 2 came nearly a year after his Serbian Progressive Party (SNS) won parliamentary elections, giving the party control over the entire legislative and governing process.

Some critics have warned that such a concentration of power could push the Balkan country back into the autocracy Milosevic symbolized during his decade in power.

The U.S. delegation is headed by Hoyt Brian Yee, deputy assistant secretary of state for European and Eurasian affairs, while Russia will be represented by Deputy Prime Minister Dmitry Rogozin. Both met with Vucic on June 23.

The presidents of five neighboring countries -- Slovenia, Croatia, Macedonia, Montenegro, and Bosnia-Herzegovina -- also attended and met with Vucic during the ceremony. They included all three members of Bosnia-Herzegovina's tripartite presidency.

Germany was represented by former Chancellor Gerhard Schroeder. Beijing sent the vice president of the Standing Committee of China's National People's Congress, Ji Bingxuan, as its representative.

They also were joined by senior officials from Hungary, Romania, Bulgaria, Italy, Greece, Armenia, Azerbaijan, Belarus, and Austria.

However, many Serbian opposition politicians boycotted the ceremony and held a protest in the Belgrade city center instead.

While Vucic pledges to prepare the nation of 7.3 million people for EU accession by 2019, he also opposes joining NATO and is pushing for deeper economic and diplomatic ties with longtime ally Moscow.

Meeting with Rogozin ahead of the inauguration, Vucic pledged that Serbia will not join Western sanctions imposed on Russia for its actions in Ukraine, despite EU suggestions that Belgrade must align its foreign policies if it wants to join the bloc.

Earlier in June, Vucic won praise for naming the minister of public administration and local government, Ana Brnabic, as the next prime minister.

The move made Brnabic the first openly gay prime minister in the Balkan region and the first Serbian woman in the government's top job.

Her appointment to the government last year was hailed by rights groups as historic for the Balkan country, whose gay community often faces discrimination, harassment, and violence.

Vucic has promised to boost gay rights as part of efforts to move closer to EU membership.

RFE/RL's Balkan Service promotes the values of democracy, human rights, and freedom of expression in a region where genuine media freedom remains elusive and where many media outlets remain divided along ethnic lines.